Unparseable output with type-level tuples and NoListTuplePuns

[amesgen]

Formatting

{-# Language NoListTuplePuns #-}

type X = (Int, String)

fails with

<input>:3:10-23
  Parsing of formatted code failed:
  [GHC-52943] Disambiguating data constructors of tuples and lists is disabled.
Remove the quote to use the data constructor.

as the output with --unsafe is

{-# LANGUAGE NoListTuplePuns #-}

type X = '(Int, String)

which is invalid when ListTuplePuns is disabled.

Environment

• Version of the code: Current master (bb9e7b1)

Additional context
While we could do a hacky fix already now, #1140 allows us to fix this in a nicer way because HsExplicitTuple tracks the PromotionFlag directly there; and this issue doesn't seem very major as only very few people are currently using NoListTuplePuns.